WO2011038858A1

WO2011038858A1 - Device for dialysis treatment and method for balancing fresh and used dialysis liquid

Info

Publication number: WO2011038858A1
Application number: PCT/EP2010/005826
Authority: WO
Inventors: Manfred Weis; Martin Lauer; Stefan Kreber
Original assignee: Fresenius Medical Care Deutschland Gmbh
Priority date: 2009-09-29
Filing date: 2010-09-23
Publication date: 2011-04-07
Also published as: EP2482868B1; EP2482868A1; JP5728015B2; CN102548595B; US20120223016A1; JP2013505750A; IN2012DN02059A; US9814818B2; CN102548595A

Abstract

The invention relates to a device for dialysis treatment which has means (12) for balancing fresh and used dialysis liquid. Furthermore, the invention relates to a method for balancing fresh and used dialysis liquid. The device according to the invention for dialysis treatment and the method according to the invention for balancing fresh and used dialysis liquid are characterized in that the individual balancing chambers (A, B, C, D) of the balancing system hold both fresh dialysis liquid and used dialysis liquid, the functions of the chambers being interchanged alternately. As a result, exact balancing can be achieved even when the volumes of the individual chambers differ from one another. Over the entire treatment period, the deviations between the volumes balance one another out because of the cyclic interchanging of the chambers.

Description

Device for dialysis treatment and

Method for balancing fresh and spent dialysis fluid

The invention relates to a device for dialysis treatment, which has means for balancing fresh and spent dialysis fluid. Moreover, the invention relates to a method for balancing fresh and spent dialysis fluid.

For the removal of urinary substances and for the removal of fluids in chronic renal failure, various methods are used for apparative blood purification or blood treatment. In hemodialysis (HD) the diffusive predominates

Mass transfer, while in hemofiltration (HF) a convective mass transport via the semipermeable membrane of the dialyzer or filter takes place. A combination of both methods is hemodiafiltration (HDF). If, in the following, a dialyzer is mentioned, a dialyzer is also understood to mean a filter.

Because of the large amounts of replacements, there is a need for accurate balancing of the fresh dialyzing fluid supplied to the dialyzer and the spent product discharged from the dialyzer in the above method

Dialysis fluid, taking into account the amount of liquid withdrawn from the patient via the membrane of the dialyzer over the entire treatment time. The prior art includes gravimetric and volumetric balancing systems. The amount of liquid withdrawn from the patient by ultrafiltration can be partially or completely re-supplied to the patient as a pyrogen-free dialysate or substituate under controlled dehydration. The supply of pyrogen-free dialysate or substituate in the extracorporeal blood circulation upstream of the dialyzer is referred to as pre-dilution and the supply of dialysate or substituate downstream of the dialyzer as post-dilution. Both methods can also be combined with each other. DE-A-28 38 414 describes a dialysis machine with a balancing system, which has two balancing chambers whose balancing chamber halves are alternately filled with fresh dialysing fluid with rejection of used dialyzing fluid from the respective other chamber half. The part of the fluid circuit enclosed between the balancing system and the dialyzer therefore behaves like a closed system whose volume is constant. Via an ultrafiltration pump, liquid can be withdrawn from the closed system. In the case of a fluid withdrawal, a pressure gradient arises on the semipermeable membrane of the dialyzer, which results in the patient being deprived of the same amount of fluid as liquid is withdrawn from the closed system with the ultrafiltration pump.

For the dialysis treatment is of great importance that the patient through

Ultrafiltration withdrawn amount of liquid is precisely determinable. Therefore, very high demands are placed on the accuracy of the balancing. However, this requires that the balancing chambers of the balancing systems make it possible to exactly balance fresh and used dialysis fluid. Because even minor errors in the balance in the successive work cycles of the balancing system can accumulate over the entire treatment period to no longer tolerable false balances.

Volumetric balancing systems are known in which fresh or used dialysis fluid is pumped into or out of the balancing chambers with pumps. But there are also accounting systems are known in which of a membrane in two

Chamber halves subdivided balancing chambers are acted upon with a working fluid to promote fresh or spent dialysis fluid.

DE-A-198 30 928 describes a dialysis apparatus with a volumetric balancing system whose balancing chambers are designed as a disposable disposable. The balancing system comprises a total of four balancing chambers, which are each subdivided by a membrane into two balancing chamber halves. One of the two balance chamber halves will be used to promote fresh or spent

Dialysis fluid, which is located in the other half of the chamber, with a Working fluid applied. The four balance chambers form a first pair of

Balancing chambers intended for the delivery of fresh dialysis fluid and a second pair of balancing chambers intended for the promotion of spent fluid

Dialysis fluid are determined. The fresh dialysis fluid is from a dialysis fluid with the two balancing chambers of a pair of

Balancing chambers promoted to the dialysis fluid chamber of the dialyzer. The spent dialysis fluid from the dialysis fluid chamber of the dialyzer is delivered to an outlet with the two balance chambers of the other pair of balance chambers. The respective balance chamber halves of the balance chambers are alternately filled with fresh or spent dialysis fluid, so that the dialysis fluid flows continuously through the dialysis fluid chamber of the dialyzer.

To the respective balance chambers alternately with fresh and spent

To be able to fill dialysis fluid, the associated balance chamber halves are in the leading from the dialysis fluid to the dialysis fluid chamber of the dialyzer supply line for fresh dialysis fluid or in the of

Dialysis fluid out of the dialyzer and connected to the outlet discharge line for spent dialysis fluid. There are Absparorgane in the respective branches of the supply and discharge line to control the flow of liquid can. The entire flow guidance and control is neither intended nor suitable for using the balancing chambers of the one pair of balancing chambers intended for conveying fresh dialysis fluid for conveying spent dialysis fluid and vice versa.

The disadvantage is that an exact accounting of fresh and used

Dialysis requires that the volumes of the individual balance chamber halves are exactly equal. But that places particularly high demands on the

Manufacturing tolerances, which are to be complied with a high level of technical complexity, especially in a disposable designed as an arrangement of balancing chambers. From US 2005/0000868 AI also a balancing system is known that has four balance clamps, which are balanced against the patient to be supplied substituate and withdrawn via the membrane of the dialyzer filtrate against each other. Also in this balancing system, two chambers each form a pair of chambers that receive either substituate or filtrate. For filling and emptying the chambers are pumps in the supply and discharge lines. Therefore, the chambers themselves need not be divided by a membrane into two chamber halves.

The invention has for its object to provide a device for dialysis treatment, which allows accurate accounting of fresh and spent dialysis fluid. Moreover, it is an object of the invention to provide a method for the accurate accounting of fresh and spent dialysis fluid.

The solution of these objects is achieved according to the invention with the features of

Claims 1 and 10. Advantageous embodiments of the invention are

Subject of the dependent claims.

The device according to the invention for dialysis treatment and the method according to the invention for balancing fresh and spent dialysis fluid are distinguished by the fact that the individual balancing camisers of the balancing system receive both fresh dialysis fluid and used dialysis fluid, the functions of the chambers being alternately reversed. As a result, exact balancing can be achieved even if the volumes of the individual chambers differ from one another. Over the entire treatment period, the deviations of the volumes due to the cyclic exchange of the chambers compensate each other.

For the invention is irrelevant how fresh and used dialysis fluid supplied to the individual balancing chambers and fresh and used dialysis fluid is discharged from the individual balancing chambers. In the device according to the invention for dialysis treatment, the means for conducting fresh and spent dialysis fluid, which are preferably tubing, are designed such that fresh dialysis fluid from a dialysis fluid source can be supplied to each balance chamber and fresh dialysis fluid from each balance chamber of the dialysis fluid chamber

Dialyzer can be performed, and used dialysis fluid from the

Dialysing fluid chamber of the dialyzer each balance chamber can be supplied and spent dialysis fluid can be removed from each balance chamber. The individual balancing chambers are each filled with fresh or used dialysis fluid in successive working cycles or the balancing chambers filled with fresh or used dialysis fluid are emptied. The four balancing chambers form two pairs of balancing chambers, wherein in each cycle from a Bilanzkan mer of a pair of Bilanzkammem the dialysis fluid fresh Dialysierflüssigkeit supplied and the other balance chamber of a pair of Bilanzkammem spent dialyzing fluid from the dialysis fluid chamber is fed during a balance chamber of the other A pair of balance chambers from the dialysis fluid source supplied fresh dialysis fluid and consumed from the other balance chamber of the other pair of balance chamber

Dialysis fluid is discharged. In the successive work cycles, the functions of the individual Bilanzkammem are mutually interchanged, so that

Deviations in the volumes of the Bilanzkammem over the entire duration of treatment can compensate.

For the invention is irrelevant how the dialysis fluid into or out of the

Balancing chamber is promoted. In a preferred embodiment of the invention, the balancing chambers for conveying fresh or spent

Dialyzing fluid is subjected to an overpressure or a negative pressure can be pressed with the fresh or spent dialysis fluid from the chamber or sucked into the chamber. The means for conveying dialysis fluid further preferably have means for opening and shutting off the means for conducting dialysis fluid, preferably means for opening and shutting off the

Hose lines to control the flow of liquid can. However, in principle it is also possible to use a fluid instead of air to convey fresh and spent dialysis fluid with the balancing combs, as is known from the prior art. But then it is necessary, the two

Divide balance chamber with a membrane in two balance chamber halves, with one balance half of the balance for receiving fresh and spent

Dialysis fluid and the other balance chamber half for receiving the working fluid is used. Furthermore, it is also possible, instead of compressed air or a working fluid to promote the dialysis fluid with pumps, as is known from the prior art.

Since each two Bilanzkammem communicate with each other, it is in principle possible to generate only in one of the two Bilanzkammem a positive pressure, while the other balance chamber is vented. On the other hand, it is also possible to generate a negative pressure in only one of the two Bilanzkammem, while the other

Balancing chamber is ventilated. Preferably, in the one balance chamber

Overpressure and generates a negative pressure in the other balance chamber.

In a further preferred embodiment, the means for conveying dialysis fluid on means for measuring the level of the Bilanzkammem, wherein the control unit is designed such that the means for opening and shutting in

Depending on a predetermined value for the level in the Bilanzkammem be opened or closed. This ensures that at a certain level, the liquid flow is interrupted. This level does not need to correspond to the maximum filling volume of the balancing chamber. For accurate balancing of fresh or used dialysis fluid, where the amount of fresh

Dialysis fluid should correspond exactly to the amount of used dialysis fluid, the same value for the level is given for all Bilanzkammem.

A particularly preferred embodiment provides the possibility of supplying the patient with liquid or withdrawing liquid over the duration of the treatment. In this embodiment, two different values for the level of the Bilanzkammem be given. In this case, the one balance chamber of the one pair of Bilanzkammem, of the fresh dialysis fluid of the dialysis fluid chamber is supplied to the first level value while the other balance chamber of the one pair of balance chambers supplied with used dialysis fluid from the dialysis fluid chamber is filled to a second level value, the first value being from the second level is different.

Accordingly, one balance chamber is filled by the other pair of balancing chambers supplied with fresh dialyzing fluid from the dialyzing fluid source to the first level value, while the other balancing chamber is filled by the other pair of balancing chambers from the used dialyzing fluid

Dialysing fluid chamber is discharged, is filled to the second value for the level. The difference between the first and the second value corresponds to the amount of liquid which is withdrawn via the membrane of the dialyzer from the patient or supplied to the patient. If the first level value is less than the second level value, filtrate is withdrawn from the patient's blood. Here, different values for the level in one or more or all

Working cycles of a cycle are specified, whereby only one, two, three or four chambers are filled differently. The ultrafiltration amount then results from the sum of the level differences of the participating balancing chambers. The deviations in the individual difference volumes possibly resulting from the desired value of the ultrafiltration rate to be set by the treating physician due to production tolerances or measurement errors are, on account of the comparatively small differences

Level differences are significantly smaller than the deviations that result in normal operation of the balancing chambers.

In a further preferred embodiment, the means for balancing fresh and spent dialysis fluid are designed as Disposable intended for single use. As a result, the equipment of the dialysis machine with permanently installed balancing chambers becomes superfluous. In addition, eliminates the costly

Sterilization of the remaining fluid-carrying parts in the machine. The formation of a balance system as disposable is known to the skilled person as such. Such a disposable is known for example from DE 198 30 928 Clund DE 195 46 028 C2. In the following, two exemplary embodiments of the invention will be explained in more detail with reference to the drawings.

Show it:

1 shows a device for dialysis in a highly simplified schematic representation, wherein the first working cycle of a working cycle is shown.

2 shows the dialysis apparatus of FIG. 1, wherein the second working cycle of the working cycle is shown, FIG.

3 shows the dialysis apparatus, wherein the third working cycle of the working cycle is shown,

4 shows the dialysis apparatus, wherein the fourth working cycle of the working cycle is shown,

FIG. 5 shows the dialysis apparatus of FIG. 1, showing the first cycle of the working cycle in the case of ultrafiltration, FIG.

6 shows the dialysis apparatus of FIG. 5, wherein the second power stroke is shown, FIG.

, FIG. 7 shows the dialysis apparatus, the third working clock being shown, and FIG

Fig. 8, the dialysis machine, wherein the fourth power stroke is shown.

FIGS. 1-4 show the essential components of a dialysis apparatus in a highly simplified schematic representation for the individual working cycles of a four

Working cycle comprehensive cycle in the event that the patient is not deprived of liquid. Figures 5-8 show the workstakes of the dialysis machine in the event that liquid is withdrawn from the patient. The individual components of the

Dialysis devices are provided in the figures with the same reference numerals. The dialysis apparatus has a dialyzer 1, which is subdivided by a semipermeable membrane 2 into a blood chamber 3 and a dialysis fluid chamber 4. At the inlet of the blood chamber 3, a blood supply line 5 is connected, in which a blood pump 6 is connected. Downstream of the blood chamber, a blood discharge line 7 leads from the outlet of the blood chamber to the patient.

In a dialysis fluid source 8 fresh dialysis fluid is provided. From the dialysis fluid source 8, a dialysis fluid supply line 9 leads to the inlet of the dialysis fluid chamber 4 of the dialyzer, while a

Dialysing fluid discharge line 10 from the outlet of the dialysis fluid chamber of the dialyzer leads to an outlet 11. For the balancing of fresh and spent dialysis fluid, a balancing device is provided, which is described in the following

Individual is described.

The balancing device 12 comprises a total of four balancing chambers, which are designated A, B, C and D. All balancing chambers A, B, C, D have the same structure. These are parts of a disposable disposable. The

Balancing chambers A, B, C, D each have an inlet (outlet) IA, IB, IC, ID and an inlet or outlet (port) OA, OB, OC, OD. In addition, the balancing chambers A, B, C, D each have a connection PA, PB, PC, PD, where only hinted means P for generating an overpressure and / or negative pressure in the balancing chambers A, B, C, D connected are.

The balancing chambers A, B, C, D are connected both in the dialysis fluid supply 9 and in the dialysis fluid discharge line 10, wherein the individual

Balancing chambers can be integrated with associated shut-off devices in the liquid flow or separated from the liquid flow. Everyone is

Balance chamber A, B, C, D each four shut-off valves VI - VI 6 assigned. The interconnection of the balancing chambers is described in detail below.

The dialysis fluid supply line 9 has a first line section 9 ', which leaves the dialysis fluid source 8. From the first Leirungsabschnitt 9 'branches four branch lines 9 ", each leading to the inlet I of the balancing chambers A, B, C, D. The stub lines 9" connect the shut-off valves V2, V6, V10 and V14. From the outlet of the balancing chambers A, B, C, D in each case a stub 9 '' from which leads to a second Leitungsabschnit 9 "" the Dialysierflüssigkeitszufuhrleitung 9. In the branch lines 9 '"are the shut-off valves V3, V7, VI 1 and VI 5 switched.

The dialysis fluid discharge line 10 has a first line section 10 ', which leaves from the outlet of the dialysis fluid chamber 4 of the dialyzer 1. Four branch lines 10 "branch off from the first power section 10 ', each leading to the outlet O of the balancing chambers A, B, C, D. The stubs 10" connect the shut-off devices S4, S8, S12 and S16. From the inlet I of the balancing chambers A, B, C, D in each case a stub 10 '"leads to a second Leitungsabschnit 10" "the Dialysierflüssigkeitsabführleitung 10. In the branch lines LO" "the shut-off valves VI, V5, V9 and V13 are connected.

In addition, the dialysis device has a central control unit 13 which opens or closes the shut-off valves VI-V16 via control lines S1-S16 and controls the means P for generating an overpressure or underpressure via control lines P1-P4 in such a way that in the balancing chambers an overpressure or a negative pressure is generated. The control of the shut-off can be done electrically or pneumatically or hydraulically.

During operation of the dialysis apparatus, fresh dialysis fluid, which is provided in the dialysis fluid source 8, is balanced against spent dialysis fluid, which is discharged into the outlet 11. Here are the individual

Balancing chambers A, B, C, D controlled such that they are filled with fresh or spent dialysis fluid or emptied. The control takes place in successive working cycles, each comprising four work cycles.

FIGS. 1-4 show the four working cycles of a working cycle. The shut-off elements opened by the control unit 13 are marked black. An upward arrow indicates the filling of a balance chamber, while a downward pointing arrow marks the unloading of the balance chamber. A solid arrow indicates fresh dialysis fluid, while a dashed arrow indicates used dialysis fluid.

In the first working cycle of the working cycle, the central control unit 13 opens the shut-off valves V2, V5, VI 2 and VI 5, while the control unit opens the other

Shut-off closes (Fig. 1). Thus, the four balancing chambers A, B, C, D can be subdivided into a first pair of balancing chambers A, B and a second pair of balancing chambers C, D. The balance chamber A is supplied from the Dialysierflüssigkeitsquelle 8 fresh dialysis fluid while consumed from the balance chamber B.

Dialysis fluid is discharged to the outlet 11. From the balance chamber D, the dialyzing fluid chamber 4 of the dialyzer 1 is supplied with fresh dialysis fluid, while spent dialysis fluid is removed from the dialysis fluid chamber 4 of the dialyzer 1 into the balance chamber C. The corresponding

Liquid flows are indicated in FIG. 1 by arrows. It is thus the contents of the balance chamber D via the dialysis fluid chamber of the dialyzer in the

Balance chamber C emptied.

In this case, the balancing chambers A and C, the liquid to be supplied with a negative pressure and the balancing chambers B and D, is discharged from the liquid, subjected to a negative pressure. For this purpose, the central control unit 13 controls the means P for generating an overpressure or underpressure accordingly.

The process of filling or emptying a chamber is monitored by the central control unit 13. In this case, the central control unit 13 cooperates with means 14 for monitoring the level of the individual balancing chambers A, B, C, D, which in each case via control lines Sl, S2, S3, S4 the individual balancing chambers assigned fill level sensors Fl, F2, F3, F4 has. At a given value for the

Level, which is the same in all chambers, will be the corresponding

Shut-off valves V closed. In the second stroke, the chambers B and C form the first pair of balancing chambers, while the chambers A and D form the second pair of balancing chambers. The balance chamber B is fresh dialysis fluid from the

Dialyzing fluid source 8 is supplied while discharged from the balance chamber C dialysis fluid is discharged into the outlet 11. From the balance chamber A, the dialysis fluid chamber 4 is supplied with fresh dialysis fluid, while the

Balance chamber D spent dialysis fluid from the dialysis fluid chamber is supplied. In this case, the corresponding shut-off valves V are opened again and the balancing chambers are correspondingly acted upon again by the means P for generating an overpressure or underpressure with an overpressure or underpressure.

In the third working cycle, the balance chambers C and D form the first balance chamber pair and the balance chambers A and B form the second balance chamber pair. From the

Dialysis fluid source 8 flows fresh dialysis fluid into the balance chamber C, while spent dialysis fluid from the balance chamber D flows into the outlet 11. The fresh dialysis fluid from the balance chamber B is on the

Dialysing fluid chamber 4 emptied into the balance chamber A.

In the fourth work cycle, the balancing chambers A and D form the first

Balancing chamber pair, while the balancing chambers B and C form the second balance chamber pair. Fresh dialysis fluid flows into the balance chamber D while dialyzing fluid consumed from the balance chamber A flows. At the same time, fresh dialysis fluid from the balance chamber C is emptied into the balance chamber B via the dialysis fluid chamber 4.

After the fourth cycle, the first cycle of the following cycle follows again. It turns out that the functions of the individual Bilanzkammem each be cyclically reversed, each balance chamber fresh Dialysierflüssigkeit supplied and used dialysis fluid is discharged from each balance chamber.

The cyclic exchange of the function of the individual chambers A, B, C, D causes different filling volumes, which are based on different chamber volumes or errors be compensated during level measurement, compensate during a work cycle. This will be explained below with reference to the present exemplary embodiment.

It is assumed that the filling volume of the balance chamber A 100 ml, the

Balance chamber B 110 ml, balance chamber C 90 ml and balance chamber D 105 ml. The volumes of the hose lines are to be neglected for the example. It should be noted, however, that the deviations of the volumes of the chambers B, C, D from the target value of 100 ml are unrealistically high and should serve only as an example.

In the first work cycle, the balance chamber D is emptied into the balance chamber C via the dialysis fluid chamber 4 of the dialyzer 1. The means P for generating an overpressure or negative pressure, which are referred to below as the pneumatic device P, generate an overpressure in chamber D and a negative pressure in chamber C. Accordingly, 105 ml are emptied from chamber D, but after only 90 ml

Shut-off VI 2 in the inlet of the chamber C closes. Since chamber D is not completely emptied, the obturator VI 5 remains open in the course of this chamber and the overpressure from chamber D propagates into the dialysis fluid chamber 4. There, the residual fluid due to the pressure gradient through the semipermeable

Press membrane 2 from the dialysis fluid side to the blood side. The blood of the patient so 15 ml of liquid supplied (refiltration).

In the second working cycle, the chamber A in chamber D empties via the

Dialysis fluid chamber3. Since chamber D has a larger volume than chamber A at the same filling level, the negative pressure in chamber D is maintained. As a result, 15ml of liquid from the blood side to the membrane 2 of the dialyzer

Dialysate side sucked (filtration).

In the third working cycle chamber B deflates in chamber A. It comes to a

Refiltration of 10 ml dialysis fluid. In the fourth working cycle, chamber C deflates in chamber B. There is a filtration of 20 ml of dialysis fluid. If one now accounts for the change in volume in the patient's blood, it becomes clear that the deviations in the volumes of the chambers over one working cycle balance each other out. The result is a sum of 15 ml - 5 ml + 10 ml -20 ml = 0. The patient is thus neither liquid supplied nor withdrawn liquid.

In the following it shall be clarified how an accounting error arises if the chambers are not cyclically reversed, i. the duty cycle comprises only two work cycles, one pair of chambers receiving only fresh dialysis fluid and the other pair of chambers only consuming dialysis fluid. In the first working cycle, the chamber D would empty into the chamber C. It would come to a refiltration of 15 ml. In the second cycle, the chamber A would be in chamber B empty. It would come to a filtration of 10 ml. This would result within the working cycle a sum that is 15 ml - 10ml + 15ml - 10ML = 10ml. The error is therefore not compensated.

The control of the balance chambers according to the invention has in addition to the exact

Balancing of fresh and spent dialysis fluid also has the advantage that in the case of a desired ultrafiltration within a work cycle the

Ultrafiltration amount can be accurately adjusted.

In the case of ultrafiltration, the central control unit 13 gives two different values for the filling levels FH and FL of the chambers, as will be explained below.

In order to withdraw fluid from the patient's blood (ultrafiltration), the level of the balancing chambers, which are to receive used dialysis fluid from the dialysis fluid chamber, is adjusted so that its filling level FH is above the level FL of the balancing chambers, which are filled with fresh dialysis fluid. The difference between the two levels FH - FL then corresponds to the blood withdrawn from the patient

Liquid. FIGS. 5-8 show the working cycles of the working cycle for the case of ultrafiltration. FIGS. 5-8 correspond to FIGS. 1-4. However, in FIGS. 5-8 the different fill levels FH, FL of the chambers A, B, C, D are marked with lines. With the exception of the different fill levels of the individual balance chambers, the Actuation of the balancing chambers as described with reference to FIGS. 1-4.

In the exemplary embodiment shown in FIGS. 5-8, all the balancing chambers are operated with a higher fill level for receiving used dialysis fluid than the balancing chambers which deliver fresh dialysis fluid. It is also possible, however, that only one, two or three of the four balance chambers are responsible for receiving the

used dialyzing fluid can be operated with a higher level.

In the first cycle, the fresh dialysis fluid from the balance chamber D, which has been filled in a previous cycle up to the level FL, transferred via the dialysis fluid 4 of the dialyzer 1 in the balance chamber C, wherein the balance chamber C is filled up to a level FH which is higher than the FL level. This is illustrated by the lines in Fig.5. Since this is a closed, volume-constant system, the amount of liquid which corresponds to the difference Δ = FH-FL between the two fill levels is withdrawn from the patient's blood via the membrane 2 of the dialyzer 1. In the second work cycle the

Dialysis fluid from the balance chamber A via the dialysis fluid transferred to the balance chamber D, the blood of the patient again the amount of

Liquid is withdrawn, which corresponds to the difference Δ = FH - FL of the two levels.

The third and fourth power strokes (Figures 7 and 8) correspond to the first and second power strokes at equal levels in the chambers. Here, too, an amount of liquid is withdrawn from the patient every stroke, which corresponds to the filling level difference Δ = FH-FL. The ultrafiltration rate then results from the sum of all level differences in all work cycles over the entire treatment period. Because of the comparatively small level differences, the desired

Ultrafiltration amount can be set with relatively high accuracy.

Claims

claims:

Device for dialysis treatment with a dialysis fluid source (8) for fresh dialysis fluid and an outlet (11) for spent dialysis fluid, a dialyzer (1) divided by a semipermeable membrane (2) into a blood chamber (3) and a dialysis fluid chamber (4),

Means (12) for balancing fresh and spent dialysis fluid comprising a first balance chamber (A), a second balance chamber (B), a third balance chamber (C) and a fourth balance chamber (D),

Means (9, 10, VI to VI 6) for conducting fresh dialysis fluid into the balancing chambers and removing spent dialysis fluid from the balancing chambers,

Means (P; VI to VI 6) for conveying fresh and spent

Dialysis fluid, and a control unit (13) for controlling the means for conveying fresh and spent dialysis fluid, characterized in that the means (9, 10) for conducting fresh and spent

Dialysis fluid are formed such that fresh dialysis fluid from the dialysis fluid source (8) each

Balance chamber (A, B, C, D) can be supplied and fresh dialysis fluid from each balance chamber (A, B, C, D) of the dialysis fluid chamber (4) of Dialyzer (1) can be supplied, and used dialyzing fluid from the dialysis fluid chamber (4) of the dialyzer (1) each balance chamber (A, B, C, D) can be supplied and spent dialysis fluid can be discharged from each balance chamber, and that the control unit (13) with the means (P; VI to VI 6) for conveying fresh and spent dialysis fluid cooperates such that supplied in successive cycles from a balance chamber of a pair of balancing chambers of the dialysis fluid fresh Dialysierflüssigkeit and the other balancing chamber of the pair of balancing chambers used dialyzing fluid from the dialysis fluid is supplied during a balance chamber from another pair of balancing chambers of the dialysis fluid fresh Dialysierflüssigkeit and used from the other balancing chamber of the other pair of Bilanzkammem spent dialysis fluid is dissipated.

2. Apparatus according to claim 1, characterized in that the means (P; VI to VI 6) for conveying dialysis fluid means (P) for acting on the balancing chambers with an overpressure or negative pressure and means (VI to VI 6) for opening and closing the means (9, 10) for conducting dialysis fluid.

3. Apparatus according to claim 1 or 2, characterized in that the means for conveying (P; VI to V16) of dialysis fluid means (Fl to F4) for measuring the level of the balancing chambers, wherein the control unit (13) is designed such the means (VI to VI 6) for opening and shutting off are opened or closed as a function of a predetermined value (FH, FL) for the level in the balancing chambers.

4. Apparatus according to claim 3, characterized in that the control unit (13) is designed such that a first value (FL) for the level of the

Balance chamber of the one pair of balance chambers, of the fresh one

Dialysis fluid is supplied to the dialysis fluid chamber, and a second value (FH) for the level of the other balancing chamber of the one pair of balancing chambers, the spent dialysis fluid from the

Dialysis fluid is supplied, is predetermined, wherein the first value is different from the second value.

5. Apparatus according to claim 3 or 4, characterized in that the

Control unit (13) is designed such that a first value (FL) for the level of the balance chamber of the other pair of balance chamber, the fresh

Dialysis fluid from the dialysis fluid is supplied, and a second value (FH) for the level of the other balancing chamber from the other pair of balancing chambers, is discharged from the used dialyzing fluid from the dialysis fluid, is predetermined, the first value is different from the second value ,

6. Apparatus according to claim 4 or 5, characterized in that the first value (FL) for the level is less than the second value (FH) for the level.

7. Device according to one of claims 1 to 6, characterized in that the means (9, 10) for conducting dialysis fluid, a supply line (9) for supplying fresh dialysis fluid from the dialysis fluid source (8) to the inlet of the dialysis fluid chamber (4). wherein the first balance chamber (A), the second balance chamber (B), the third balance chamber (C) and the fourth balance chamber (D) are connected in the supply line, and a discharge line (10) for discharging spent dialysis fluid from the dialysis fluid chamber (4), wherein the first balance chamber (A), the second balance chamber (B), the third balance chamber (C) and the fourth

Balance chamber (D) are connected in the discharge line.

8. The device according to claim 7, characterized in that of the first chamber (A), the second chamber (B), the third chamber (C) and the fourth chamber (D) to the supply line (9) leading stubs (9 " ) and to the discharge line (10) leading stubs (10 ") branch off, said means (VI to VI 6) arranged for opening and closing in the stubs

Shut-off valves are.

9. Device according to one of claims 1 to 8, characterized in that the balancing chambers (A, B, C, D) and the means (9, 10) for conducting fresh and spent dialysis fluid are designed as disposable.

10. A method for balancing fresh and spent dialysis fluid with a balancing device having a first balance chamber, a second balancing chamber

Balance chamber, a third balance chamber and a fourth balance chamber, characterized in that the balance chambers (A, B, C, D) are operated such that in

successive working cycles of each balance chamber of the first, second, third and fourth balance chamber fresh dialyzing fluid is supplied from each balance chamber fresh dialysis fluid of the dialysis fluid chamber of the dialyzer is supplied to each balance chamber consumed

Dialysis fluid is supplied from the dialysis fluid chamber of the dialyzer and discharged from each balance chamber spent dialysis fluid.

11. The method according to claim 10, characterized in that in

successive work cycles from a balancing chamber supplied by a pair of balancing chambers of the dialysis fluid fresh Dialysierflüssigkeit and the other balancing chamber of the pair of balancing chambers spent dialyzing fluid from the dialysis fluid is fed during a balancing chamber from another pair of balancing chambers of the dialysis fluid fresh dialysis fluid and from the other balancing chamber is drained of dialyzing fluid consumed by the other pair of balancing chambers.

12. The method according to claim 10 or 11, characterized in that for conveying dialysis fluid from the balancing chambers, an overpressure in the

Balancing chambers is generated and for conveying dialysis fluid from the balancing chambers in the balancing chambers, a negative pressure is generated.

13. The method according to any one of claims 10 to 12, characterized in that the level (FL, FH) of the balancing chambers is monitored, wherein the liquid path opened in or out of the balancing chamber as a function of a predetermined value for the level in the balancing chambers or closed.

14. The method according to claim 13, characterized in that a first value for the level (FL) of the balance chamber of the one pair of balance chambers, is supplied from the fresh dialysis fluid of the dialysis fluid, and a second value (FH) for the level of the other Balance chamber of the one pair of balancing chambers, the used dialyzing fluid is supplied from the dialysis fluid chamber, is predetermined, wherein the first value is different from the second value.

15. The method of claim 13 or 14, characterized in that a first value for the level of the balance chamber of the other pair of balancing chambers, the fresh dialysis fluid is supplied from the dialysis fluid, and a second value for the level of the other balancing chamber of the other A pair of balancing chambers, is discharged from the spent dialysis fluid from the dialysis fluid, is given, wherein the first value is different from the second value.

16. The method according to claim 15, characterized in that the first value (FL) for the level is less than the second value (FH) for the level.